1. Field of Invention
The present invention relates to nutcrackers, in particular to a nutcracker having a self-locking, hand-adjustable anvil, especially for use with macadamia and other nuts.
2. Description of Prior Art
There are many types of prior-art nutcrackers, none of which are strong enough to crack the tough Australian bush nut, otherwise known as the macadamia nut. None are attractive and all are prosaic.
Macadamia nuts have an extremely tough, yet deformable and elastic shell. In fact they are so tough to crack that they are not usually distributed for sale in the shell, but packed in airtight jars after the shell has been removed at a factory.
Factory shelled nuts, however, are not a suitable alternative compared to the delightful taste of the kernels when freshly removed from the shells: the macadamia is the richest and best flavored of all nuts, but loses a significant amount of flavor over time after it is shelled. However, the consumer is denied this elegant flavor because, insofar as I am aware, no nutcracker is available on the market which will crack these tough nuts.
In Australia, where the native macadamia grows wild, the nuts are broken open by hammer blows. Frequently, injuries occur due to the nut escaping from under the hammer and zipping off at bullet-like speed and striking bystanders, or the person wielding the hammer. Such a practice is dangerous and inconvenient and does little to promote the sale of these health-giving and flavorsome nuts.
Many nutcrackers and force applying devices have been proposed but, as stated, are not suitable for use with the macadamia.
R. L. Glidden in U.S. Pat. No. 1,358,145, dated Nov. 9, 1920, shows a bottle capper which uses a lever with a fixed pivot point and a handle. At a point therebetween is a pivoted pressure capper positioned at ninety degrees to the lever, such that multiplied force can be obtained by applying hand force to the handle. The degree of force applied can easily be calculated by dividing the distance from pivot 25 and pivot 23 into the length of lever 22. This is about 8 to 1. However an 8-to-1 leverage is not nearly enough to crack a macadamia nut, or even a Brazil nut. Also this device has to be post mounted and is not attractive.
J. F. Miller, in U.S. Pat. No. 1,665,557, dated Apr. 10, 1928, teaches a lever type nutcracker which is table mounted. A lever is pivoted at one end to the mounted housing and has an operating handle at the opposite end. The housing also has a fixed anvil 4 against which nuts can be placed. A slide 13 engages the other side of the nut and an actuating arm 14 connects slide 13 to an intermediate pressure pivot point 25 on lever 22, such that by activating the lever, it pushes arm 14, which in turn forces slide 13 to engage a nut against anvil 4.
One of the problems with this device is that it must be specifically adjusted for each different nut sizes. This is accomplished by providing different notches. However, this will not work for macadamia nuts because their shells have excellent elastic properties and distort under pressure to a large degree before cracking occurs. This could result in having to make two calculated adjustment positions to accomodate the very resistant and elastic property of the shell of the macadamia nut. Also this device has to be table mounted, and is complex in design and is unnatractive in appearance.
J. Weimer, in U.S. Pat. No. 1,791,992, dated Jan. 12, 1931, teaches a hand-held nutcracker which has a fixed anvil 3 attached to one handle 4 against which a nut can be placed. Handle 4 also incorporates a slide section 2 on which a slide member 10 cooperates and which carries a moving jaw 7 and a toothed rachet 9. A second handle 16 is pivoted to a carrier and carries a pawl 20, such that when handle 16 is closed, pawl 20 urges jaw 7 toward jaw 3 to crack a nut placed therebetween.
There are a number of deficiencies with this nutcracker. First, one hand is required to hold the nut in place, while the other hand positions slide jaw 7 against the nut to hold it in position. Then a hand has to be moved to the handles to close them so as to crack the nut. If the nut simply distorts, but doesn't crack, as a macadamia nut will do, then the handle has to be opened to engage a new ratchet grip, and a second try made to crack the nut. Another problem is that a child cannot be expected to use it, because a child's hand cannot open wide enough to grasp the handles, nor exert enough force to close the jaws against a macadamia nut, or any other hard-to-break nut.
F. W. Woods, in U.S. Pat. No. 1,922,515, dated Aug. 15, 1933, shows a nutcracker which has to be screwed to a table or post. Therefore it cannot be passed from person to person. Also it requires a number of highly machined parts. In operation lug 20, which has a rounded surface, comes into contact with the flat end of stem 7. This takes place when the pressure between them is excessive, i.e., enough to crack a nut. At the same time, since lug 20 is moving in an arc, and stem 7 is moving axially, there is a sliding action taking place,between these two parts which will cause excessive wear. Furthermore the device is not attractive.
M. Paul, in U.S. Pat. No. 2,572,378, dated Oct. 23, 1951, shows a nutcracker and ice crusher which is similiar to device in the Glidden patent, supra. It has a leverage of about eight-to-one, which is not nearly sufficient to crack a macadamia nut.
H. H. Smith, in U.S. Pat. No. 2,563,379, dated Aug. 7, 1951, shows a can crusher. This device is similiar to those of M. Paul and Glidden patents, supra, and likewise has insufficient leverage to crack macadamia nuts.
T. B. Conner, in U.S. Pat. No. 2,827,087, dated Mar. 18, 1958, shows a reciprocrating nutcracker which has the same problems as the devices of Smith, Paul, and Glidden. Also it must be table mounted.
L. R. Gehrke, in U.S. Pat. No. 2,505,538, dated Apr. 25, 1950, shows a nutcracker which is similiar to that of Glidden and has the same ineffective leverage.
K. H. Griemert, in U.S. Pat. No. 3,009,414, dated Nov. 21, 1961, shows a can crusher which uses a simple lever and has insufficient leverage to crack macadamia nuts.